Collaborative Research: Seismicity of the Equatorial Mid-Atlantic Ridge and its Large Offset Transforms

拴在赤道大西洋上的8个水听器记录了地震的大小和位置，这为我们提供了一个无与伦比的视角，可以看到这个地区鲜为人知的缓慢蔓延的大西洋中脊的地震活动。这些数据还允许测试地震可以在海洋转换断层处预测的想法，并且它们提供了三重连接点（三个构造板块相交的地方）如何工作的见解。赤道大西洋海底尚未被广泛研究，但由于许多原因，它很有趣。首先，大西洋中脊轴线被海洋中一些最长的转换断层所抵消。例如，罗曼切变换的长度超过900公里。在某些地方，变换偏移量非常大，以至于变换断层的总长度超过了脊轴的总长度。这些断裂带极为崎岖，是南北大西洋海底水流动的重要通道，可能是阻止热液喷口动物群沿脊轴运输的物理屏障。赤道大西洋转换是测试海洋转换断层地震的短期可预测性的理想选择，其结果可能有助于了解大陆断层的地震。该地区第二个有趣的方面是，它包含了北美、南美和非洲构造板块交汇的三重交界处。三重交界处的确切位置仍然是一个有争议的问题，这项研究将有助于确定它的位置。第三，北美和南美板块之间的板块边界位置是不知道的，即使板块之间有运动。水听器记录的地震为这两个板块的运动，以及运动发生的方式和地点提供了重要的新信息。水听器阵列还记录了各种自然和人为的噪音，并将促进广泛的研究超出了提议的工作范围。例子包括使用环境声测量来研究各种气候研究课题，包括估计飓风期间的浪高、降雨强度和风速。此外，记录下来的鲸鱼发声可以追踪这些动物在整个赤道大西洋的分布和迁徙。

The sizes and locations of earthquakes recorded by eight hydrophones moored in the Equatorial Atlantic Ocean provide an unparalleled view of the seismicity of the poorly understood slow-spreading Mid-Atlantic Ridge in this region. The data also allow testing of the idea that earthquakes can be predicted at ocean transform faults, and they provide insight into how triple junctions (where three tectonic plates meet) work. The Equatorial Atlantic seafloor has not been studied extensively but is interesting for many reasons. First, the Mid-Atlantic Ridge axis is offset on some of the longest transform faults in the oceans. As an example, the Romanche transform is greater than 900 km long. In places, the transform offsets are so large that the total length of the transform faults is longer than the total length of the ridge axis. These fracture zones are extremely rugged, are important conduits for bottom water moving between the North and South Atlantic Ocean, and probably act as physical barriers blocking the transport of hydrothermal vent fauna along the ridge axis. The Equatorial Atlantic transforms are ideal for testing the short-term predictability of earthquakes at ocean transform faults and the results may help in understanding earthquakes on continental faults. A second interesting aspect of the region is that it contains the triple junction where the North America, South America, and Africa tectonic plates meet. The exact location of the triple junction is still a matter of debate, and this study will help to define its location. Third, the location of the plate boundary between the North America and South America plates is not known even though there is motion between the plates. The earthquakes recorded by the hydrophones provide important new information about the motion of these two plates, and how and where that motion is taking place. The hydrophone array also records a variety of natural and man-made noises and will facilitate a wide-range of studies beyond the scope of the proposed work. Examples include the use of ambient sound measurements to study various climate research topics, including estimating wave heights, rainfall intensity and wind speed during hurricanes. In addition, recorded whale vocalizations allow the distribution and migration of these animals to be tracked throughout the Equatorial Atlantic Ocean.